<!DOCTYPE html><html><head><meta charset="utf-8"><style>body {
  width: 45em;
  border: 1px solid #ddd;
  outline: 1300px solid #fff;
  margin: 16px auto;
}

body .markdown-body
{
  padding: 30px;
}

@font-face {
  font-family: fontawesome-mini;
  src: url(data:font/woff;charset=utf-8;base64,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) format('woff');
}

@font-face {
  font-family: octicons-anchor;
  src: url(data:font/woff;charset=utf-8;base64,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) format('woff');
}

.markdown-body {
  font-family: sans-serif;
  -ms-text-size-adjust: 100%;
  -webkit-text-size-adjust: 100%;
  color: #333333;
  overflow: hidden;
  font-family: "Helvetica Neue", Helvetica, "Segoe UI", Arial, freesans, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  word-wrap: break-word;
}

.markdown-body a {
  background: transparent;
}

.markdown-body a:active,
.markdown-body a:hover {
  outline: 0;
}

.markdown-body b,
.markdown-body strong {
  font-weight: bold;
}

.markdown-body mark {
  background: #ff0;
  color: #000;
  font-style: italic;
  font-weight: bold;
}

.markdown-body sub,
.markdown-body sup {
  font-size: 75%;
  line-height: 0;
  position: relative;
  vertical-align: baseline;
}
.markdown-body sup {
  top: -0.5em;
}
.markdown-body sub {
  bottom: -0.25em;
}

.markdown-body h1 {
  font-size: 2em;
  margin: 0.67em 0;
}

.markdown-body img {
  border: 0;
}

.markdown-body hr {
  -moz-box-sizing: content-box;
  box-sizing: content-box;
  height: 0;
}

.markdown-body pre {
  overflow: auto;
}

.markdown-body code,
.markdown-body kbd,
.markdown-body pre,
.markdown-body samp {
  font-family: monospace, monospace;
  font-size: 1em;
}

.markdown-body input {
  color: inherit;
  font: inherit;
  margin: 0;
}

.markdown-body html input[disabled] {
  cursor: default;
}

.markdown-body input {
  line-height: normal;
}

.markdown-body input[type="checkbox"] {
  box-sizing: border-box;
  padding: 0;
}

.markdown-body table {
  border-collapse: collapse;
  border-spacing: 0;
}

.markdown-body td,
.markdown-body th {
  padding: 0;
}

.markdown-body .codehilitetable {
  border: 0;
  border-spacing: 0;
}

.markdown-body .codehilitetable tr {
  border: 0;
}

.markdown-body .codehilitetable pre,
.markdown-body .codehilitetable div.codehilite {
  margin: 0;
}

.markdown-body .linenos,
.markdown-body .code,
.markdown-body .codehilitetable td {
  border: 0;
  padding: 0;
}

.markdown-body td:not(.linenos) .linenodiv {
  padding: 0 !important;
}

.markdown-body .code {
  width: 100%;
}

.markdown-body .linenos div pre,
.markdown-body .linenodiv pre,
.markdown-body .linenodiv {
  border: 0;
  -webkit-border-radius: 0;
  -moz-border-radius: 0;
  border-radius: 0;
  -webkit-border-top-left-radius: 3px;
  -webkit-border-bottom-left-radius: 3px;
  -moz-border-radius-topleft: 3px;
  -moz-border-radius-bottomleft: 3px;
  border-top-left-radius: 3px;
  border-bottom-left-radius: 3px;
}

.markdown-body .code div pre,
.markdown-body .code div {
  border: 0;
  -webkit-border-radius: 0;
  -moz-border-radius: 0;
  border-radius: 0;
  -webkit-border-top-right-radius: 3px;
  -webkit-border-bottom-right-radius: 3px;
  -moz-border-radius-topright: 3px;
  -moz-border-radius-bottomright: 3px;
  border-top-right-radius: 3px;
  border-bottom-right-radius: 3px;
}

.markdown-body * {
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

.markdown-body input {
  font: 13px Helvetica, arial, freesans, clean, sans-serif, "Segoe UI Emoji", "Segoe UI Symbol";
  line-height: 1.4;
}

.markdown-body a {
  color: #4183c4;
  text-decoration: none;
}

.markdown-body a:hover,
.markdown-body a:focus,
.markdown-body a:active {
  text-decoration: underline;
}

.markdown-body hr {
  height: 0;
  margin: 15px 0;
  overflow: hidden;
  background: transparent;
  border: 0;
  border-bottom: 1px solid #ddd;
}

.markdown-body hr:before,
.markdown-body hr:after {
  display: table;
  content: " ";
}

.markdown-body hr:after {
  clear: both;
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4,
.markdown-body h5,
.markdown-body h6 {
  margin-top: 15px;
  margin-bottom: 15px;
  line-height: 1.1;
}

.markdown-body h1 {
  font-size: 30px;
}

.markdown-body h2 {
  font-size: 21px;
}

.markdown-body h3 {
  font-size: 16px;
}

.markdown-body h4 {
  font-size: 14px;
}

.markdown-body h5 {
  font-size: 12px;
}

.markdown-body h6 {
  font-size: 11px;
}

.markdown-body blockquote {
  margin: 0;
}

.markdown-body ul,
.markdown-body ol {
  padding: 0;
  margin-top: 0;
  margin-bottom: 0;
}

.markdown-body ol ol,
.markdown-body ul ol {
  list-style-type: lower-roman;
}

.markdown-body ul ul ol,
.markdown-body ul ol ol,
.markdown-body ol ul ol,
.markdown-body ol ol ol {
  list-style-type: lower-alpha;
}

.markdown-body dd {
  margin-left: 0;
}

.markdown-body code,
.markdown-body pre,
.markdown-body samp {
  font-family: Consolas, "Liberation Mono", Menlo, Courier, monospace;
  font-size: 12px;
}

.markdown-body pre {
  margin-top: 0;
  margin-bottom: 0;
}

.markdown-body kbd {
  background-color: #e7e7e7;
  background-image: -moz-linear-gradient(#fefefe, #e7e7e7);
  background-image: -webkit-linear-gradient(#fefefe, #e7e7e7);
  background-image: linear-gradient(#fefefe, #e7e7e7);
  background-repeat: repeat-x;
  border-radius: 2px;
  border: 1px solid #cfcfcf;
  color: #000;
  padding: 3px 5px;
  line-height: 10px;
  font: 11px Consolas, "Liberation Mono", Menlo, Courier, monospace;
  display: inline-block;
}

.markdown-body>*:first-child {
  margin-top: 0 !important;
}

.markdown-body>*:last-child {
  margin-bottom: 0 !important;
}

.markdown-body .headeranchor-link {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  display: block;
  padding-right: 6px;
  padding-left: 30px;
  margin-left: -30px;
}

.markdown-body .headeranchor-link:focus {
  outline: none;
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4,
.markdown-body h5,
.markdown-body h6 {
  position: relative;
  margin-top: 1em;
  margin-bottom: 16px;
  font-weight: bold;
  line-height: 1.4;
}

.markdown-body h1 .headeranchor,
.markdown-body h2 .headeranchor,
.markdown-body h3 .headeranchor,
.markdown-body h4 .headeranchor,
.markdown-body h5 .headeranchor,
.markdown-body h6 .headeranchor {
  display: none;
  color: #000;
  vertical-align: middle;
}

.markdown-body h1:hover .headeranchor-link,
.markdown-body h2:hover .headeranchor-link,
.markdown-body h3:hover .headeranchor-link,
.markdown-body h4:hover .headeranchor-link,
.markdown-body h5:hover .headeranchor-link,
.markdown-body h6:hover .headeranchor-link {
  height: 1em;
  padding-left: 8px;
  margin-left: -30px;
  line-height: 1;
  text-decoration: none;
}

.markdown-body h1:hover .headeranchor-link .headeranchor,
.markdown-body h2:hover .headeranchor-link .headeranchor,
.markdown-body h3:hover .headeranchor-link .headeranchor,
.markdown-body h4:hover .headeranchor-link .headeranchor,
.markdown-body h5:hover .headeranchor-link .headeranchor,
.markdown-body h6:hover .headeranchor-link .headeranchor {
  display: inline-block;
}

.markdown-body h1 {
  padding-bottom: 0.3em;
  font-size: 2.25em;
  line-height: 1.2;
  border-bottom: 1px solid #eee;
}

.markdown-body h2 {
  padding-bottom: 0.3em;
  font-size: 1.75em;
  line-height: 1.225;
  border-bottom: 1px solid #eee;
}

.markdown-body h3 {
  font-size: 1.5em;
  line-height: 1.43;
}

.markdown-body h4 {
  font-size: 1.25em;
}

.markdown-body h5 {
  font-size: 1em;
}

.markdown-body h6 {
  font-size: 1em;
  color: #777;
}

.markdown-body p,
.markdown-body blockquote,
.markdown-body ul,
.markdown-body ol,
.markdown-body dl,
.markdown-body table,
.markdown-body pre,
.markdown-body .admonition {
  margin-top: 0;
  margin-bottom: 16px;
}

.markdown-body hr {
  height: 4px;
  padding: 0;
  margin: 16px 0;
  background-color: #e7e7e7;
  border: 0 none;
}

.markdown-body ul,
.markdown-body ol {
  padding-left: 2em;
}

.markdown-body ul ul,
.markdown-body ul ol,
.markdown-body ol ol,
.markdown-body ol ul {
  margin-top: 0;
  margin-bottom: 0;
}

.markdown-body li>p {
  margin-top: 16px;
}

.markdown-body dl {
  padding: 0;
}

.markdown-body dl dt {
  padding: 0;
  margin-top: 16px;
  font-size: 1em;
  font-style: italic;
  font-weight: bold;
}

.markdown-body dl dd {
  padding: 0 16px;
  margin-bottom: 16px;
}

.markdown-body blockquote {
  padding: 0 15px;
  color: #777;
  border-left: 4px solid #ddd;
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</style><title>JS基本语法</title></head><body><article class="markdown-body"><div class="toc">
<ul>
<li><a href="#javascript">JavaScript基础语法</a><ul>
<li><a href="#_1">语言介绍</a><ul>
<li><a href="#javascript_1">JavaScript的诞生</a></li>
<li><a href="#js">js版本</a></li>
<li><a href="#js_1">js的优势</a></li>
<li><a href="#js_2">js用途</a></li>
<li><a href="#js_3">js语言的组成</a></li>
<li><a href="#jsh5">JS和H5的关系</a></li>
<li><a href="#_2">编辑工具</a></li>
</ul>
</li>
<li><a href="#_3">语法</a><ul>
<li><a href="#js_4">js代码的编写位置</a></li>
<li><a href="#js_5">JS变量的定义、关键字</a></li>
<li><a href="#js_6">JS代码规范:</a></li>
<li><a href="#js_7">JS数据类型</a></li>
</ul>
</li>
<li><a href="#_4">运算</a><ul>
<li><a href="#_5">算术运算：</a></li>
<li><a href="#_6">字符串拼接：+</a></li>
<li><a href="#_7">赋值操作：</a></li>
<li><a href="#_8">关系运算（返回布尔值）</a></li>
<li><a href="#_9">逻辑运算（返回布尔值）</a></li>
<li><a href="#_10">一元运算</a></li>
<li><a href="#_11">三目运算</a></li>
<li><a href="#_12">八进制和十六进制的介绍</a></li>
</ul>
</li>
<li><a href="#_13">参考</a><ul>
<li><a href="#_14">关键字</a></li>
<li><a href="#_15">保留字</a></li>
<li><a href="#_16">操作符优先级</a></li>
<li><a href="#_17">术语</a></li>
</ul>
</li>
</ul>
</li>
</ul>
</div>
<h1 id="javascript"><a name="user-content-javascript" href="#javascript" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>JavaScript基础语法</h1>
<h2 id="_1"><a name="user-content-_1" href="#_1" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>语言介绍</h2>
<h3 id="javascript_1"><a name="user-content-javascript_1" href="#javascript_1" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>JavaScript的诞生</h3>
<p>JavaScript 诞生于 1995 年。由Netscape(网景公司)的程序员Brendan Eich(布兰登)与Sun公司联手开发一门脚本语言,  最初名字叫做Mocha，1995年9月改为LiveScript。12月，Netscape公司与Sun公司（Java语言的发明者）达成协议，后者允许将这种语言叫做JavaScript。这样一来，Netscape公司可以借助Java语言的声势。</p>
<p>1996年3月， Netscape公司的浏览器Navigator2.0浏览器正式内置了JavaScript脚本语言.  此后其他主流浏览器逐渐开始支持JavaScript. </p>
<h3 id="js"><a name="user-content-js" href="#js" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>js版本</h3>
<blockquote>
<p>JavaScript这种语言的基本语法结构是由ECMAScript来标准化的, 所以我们说的JavaScript版本一般指的是ECMAScript版本.</p>
</blockquote>
<ul>
<li>1997年7月，ECMAScript 1.0发布。</li>
<li>1998年6月，ECMAScript 2.0版发布。</li>
<li>1999年12月，ECMAScript 3.0版发布。</li>
<li>2007年10月，ECMAScript 4.0版草案想要提交ECMA组织, 但由于4.0版的目标过于激进, 改动太大, 并且微软,谷歌等大公司极力反对；一直到2008年7月ECMA开会决定，中止ECMAScript 4.0的开发（即废除了这个版本）</li>
<li>2009年12月，ECMAScript 5.0版正式发布</li>
<li>2011年6月，ECMAscript 5.1版发布</li>
<li>2015年6月，ECMAScript 6正式发布，并且更名为“ECMAScript 2015”。</li>
</ul>
<h3 id="js_1"><a name="user-content-js_1" href="#js_1" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>js的优势</h3>
<p>目前苹果公司的Safari, 谷歌的Chrome,微软的IE等几乎全部浏览器都支持JavaScript, 基于JavaScript开发的库和框架数不胜数, 例如: jQuery, PhoneGap, Angular, React等…</p>
<p>JavaScript将在前端和服务器端(Node.js)有更好的发展</p>
<h3 id="js_2"><a name="user-content-js_2" href="#js_2" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>js用途</h3>
<p>它的主要目的是，验证发往服务器端的数据、增加 Web互动、加强用户体验度等。可用于开发网站、游戏、移动端app等</p>
<h3 id="js_3"><a name="user-content-js_3" href="#js_3" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>js语言的组成</h3>
<blockquote>
<p>javascript = ECMAScript + BOM + DOM</p>
</blockquote>
<ol>
<li>核心(ECMAScript)</li>
<li>浏览器对象模型(BOM)</li>
<li>文档对象模型(DOM)</li>
</ol>
<h3 id="jsh5"><a name="user-content-jsh5" href="#jsh5" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>JS和H5的关系</h3>
<p>h5全称html5,不是单纯的html的第5个版本，而是一项最新的web标准，是html、css、javascript等技术的集合</p>
<h3 id="_2"><a name="user-content-_2" href="#_2" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>编辑工具</h3>
<ul>
<li>sublime Text</li>
<li>HBuilder</li>
<li>Dreamweaver</li>
<li>Notepad++等</li>
</ul>
<h2 id="_3"><a name="user-content-_3" href="#_3" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>语法</h2>
<h3 id="js_4"><a name="user-content-js_4" href="#js_4" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>js代码的编写位置</h3>
<ul>
<li>html属性<br />
<code>&lt;a href="javascript:alert(100)"&gt;&lt;/a&gt;</code></li>
<li>script标签<br />
<pre><code>&lt;script type=&quot;text/javascript&quot;&gt;
    alert('你好')
&lt;/script&gt;
</code></pre><br />
script标签属性<ul>
<li>type:类型(可选)</li>
<li>src :js文件路径<br />
    带src属性的script标签内不能写js代码</li>
</ul>
</li>
<li>js文件<br />
独立的js文件需要引入页面才能执行<br />
<pre><code>&lt;script type=&quot;text/javascript&quot; src=&quot;js/common.js&quot;&gt;&lt;script&gt;
</code></pre></li>
</ul>
<h3 id="js_5"><a name="user-content-js_5" href="#js_5" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>JS变量的定义、关键字</h3>
<ul>
<li>
<p>变量定义(使用var关键字)：变量是存储信息的容器<br />
<code>var age;       //var 是关键字，age是变量名</code></p>
</li>
<li>
<p>赋值：<br />
<code>age = 20;</code></p>
</li>
<li>
<p>定义的同时赋值：<br />
<code>var age=20;</code></p>
</li>
<li>
<p>可以一次定义多个变量：<br />
<code>var name="zhangsan", age=18, weight=108;</code></p>
</li>
</ul>
<h3 id="js_6"><a name="user-content-js_6" href="#js_6" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>JS代码规范:</h3>
<ul>
<li>JS变量的命名规范<ul>
<li>变量名可以是数字,字母,下划线_和美元符$组成;</li>
<li>第一个字符不能为数字</li>
<li>不能使用关键字或保留字</li>
<li>标识符区分大小写，如：age和Age是不同的变量。但强烈不建议用同一个单词的大小写区分两个变量。</li>
<li>变量命名尽量遵守驼峰原则: myStudentScore</li>
<li>变量命名尽量见名知意</li>
</ul>
</li>
<li>保持代码缩进</li>
<li>JS语句的末尾尽量写上分号;</li>
<li>运算符两遍都留一个空格, 如 var n = 1 + 2;</li>
<li>注释<ul>
<li>单行注释：//注释内容</li>
<li>多行注释（和CSS注释一样）<ul>
<li><code>/*注释内容*/</code></li>
<li>多行注释不能嵌套</li>
</ul>
</li>
</ul>
</li>
</ul>
<h3 id="js_7"><a name="user-content-js_7" href="#js_7" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>JS数据类型</h3>
<ul>
<li>基本数据类型<ul>
<li>Number：数字<br />
整型和浮点型<ul>
<li>toFixed(num): 在数字后面调用，num为小数为，有四舍五入的功能，得到一个字符串</li>
<li>Math.round()<br />
四舍五入取整</li>
<li>parseInt()</li>
<li>parseFloat()</li>
</ul>
</li>
<li>String：字符串<br />
用引号（单/双引号）括起来的内容</li>
<li>Boolean: 布尔类型<br />
Boolean 类型有两个值：true和false</li>
</ul>
</li>
<li>引用数据类型<ul>
<li>Array：数组 </li>
<li>Object：对象</li>
</ul>
</li>
<li>
<p>特殊数据类型</p>
<ul>
<li>Null<br />
Null 类型是一个只有一个值的数据类型，即特殊的值 null。它表示一个空对象引用(指针)，而 typeof 操作符检测 null 会返回 object</li>
<li>Undefined<br />
Undefined类型只有一个值，即特殊的 undefined，在使用 var 声明变量，但没有对其初始化时，这个变量的值就是 undefined<ul>
<li>与not defined的区别(not defined:未声明)</li>
</ul>
</li>
<li>NaN<br />
是一个特殊的值，即非数值(Not a Number)。数学运算无法得到数字时，就会返回NaN<ul>
<li>不代表任何值，也不等于任何值，甚至自己都不等于自己</li>
<li>任何数据与它运算都返回NaN</li>
<li>isNaN(a)：用来判断a到底是不是非数字,返回布尔值</li>
</ul>
</li>
</ul>
</li>
<li>
<p>数据类型判断</p>
<ul>
<li>typeof<br />
<pre><code>typeof 'html5'; //=&gt;string
typeof 100; //=&gt;number
typeof true //=&gt;boolean
typeof null //=&gt;object
</code></pre></li>
</ul>
</li>
<li>
<p>数据类型转换</p>
<ul>
<li>基本数据类型转换：利用内置函数进行转换</li>
</ul>
<table>
<thead>
<tr>
<th>值(a)</th>
<th align="center">转换为</th>
<th></th>
<th></th>
<th></th>
</tr>
</thead>
<tbody>
<tr>
<td></td>
<td align="center"></td>
<td>字符串String(a)</td>
<td>数字Number(a)</td>
<td>布尔值Boolean(a)</td>
</tr>
<tr>
<td>undefined</td>
<td align="center">=&gt;</td>
<td>&lsquo;undefined&rsquo;</td>
<td>NaN</td>
<td>false</td>
</tr>
<tr>
<td>null</td>
<td align="center">=&gt;</td>
<td>&lsquo;null&rsquo;</td>
<td>0</td>
<td>false</td>
</tr>
<tr>
<td>true</td>
<td align="center">=&gt;</td>
<td>&lsquo;true&rsquo;</td>
<td>1</td>
<td></td>
</tr>
<tr>
<td>false</td>
<td align="center">=&gt;</td>
<td>&lsquo;false&rsquo;</td>
<td>0</td>
<td></td>
</tr>
<tr>
<td>&rdquo;&ldquo;</td>
<td align="center">=&gt;</td>
<td></td>
<td>0</td>
<td>false</td>
</tr>
<tr>
<td>&ldquo;1.2&rdquo;</td>
<td align="center">=&gt;</td>
<td></td>
<td>1</td>
<td>true</td>
</tr>
<tr>
<td>&ldquo;one&rdquo;</td>
<td align="center">=&gt;</td>
<td></td>
<td>1</td>
<td>true</td>
</tr>
<tr>
<td>0</td>
<td align="center">=&gt;</td>
<td>&ldquo;0&rdquo;</td>
<td></td>
<td>false</td>
</tr>
<tr>
<td>-0</td>
<td align="center">=&gt;</td>
<td>&ldquo;0&rdquo;</td>
<td></td>
<td>false</td>
</tr>
<tr>
<td>NaN</td>
<td align="center">=&gt;</td>
<td>&ldquo;NaN&rdquo;</td>
<td></td>
<td>false</td>
</tr>
<tr>
<td>Infinity</td>
<td align="center">=&gt;</td>
<td>&ldquo;Infinity&rdquo;</td>
<td></td>
<td>true</td>
</tr>
<tr>
<td>-Infinity</td>
<td align="center">=&gt;</td>
<td>&ldquo;-Infinity&rdquo;</td>
<td></td>
<td>true</td>
</tr>
<tr>
<td>1</td>
<td align="center">=&gt;</td>
<td>&ldquo;1&rdquo;</td>
<td></td>
<td>true</td>
</tr>
</tbody>
</table>
<ul>
<li>隐式转换<br />
如果运算不能进行下去，内部就会尝试进行数据类型的转换<br />
支持隐式转换的运算：逻辑运算、关系运算、数学运算</li>
</ul>
</li>
</ul>
<h2 id="_4"><a name="user-content-_4" href="#_4" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>运算</h2>
<h3 id="_5"><a name="user-content-_5" href="#_5" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>算术运算：</h3>
<p>+, -, *, /, %:加,减,乘,除,取余(取模)</p>
<h3 id="_6"><a name="user-content-_6" href="#_6" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>字符串拼接：+</h3>
<p>在js内的运算更偏爱于字符串拼接<br />
一个引号引发的公司倒闭</p>
<h3 id="_7"><a name="user-content-_7" href="#_7" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>赋值操作：</h3>
<ul>
<li>=<br />
<code>var num1=10;//表示把10赋值给num1变量</code></li>
<li>+=：在原来的内容基础上追加内容<br />
<code>str += 'test' &lt;==&gt; str = str + 'test'</code></li>
<li>-=：<br />
<code>var n=10; n -= 2 &lt;==&gt; n = n - 2</code></li>
<li>*=,/=,%=</li>
</ul>
<h3 id="_8"><a name="user-content-_8" href="#_8" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>关系运算（返回布尔值）</h3>
<ul>
<li>==(等于), !=(不等于)</li>
<li>&lt;(小于)、&gt;(大于)、&lt;=(小于等于)、&gt;=(大于等于)</li>
<li>===、恒等于/全等于，比较的时候要求值和类型都相等（不会进行类型隐式转换）</li>
<li>
<p>!==、不全等于</p>
</li>
<li>
<p>关系运算符的比较规则: <br />
1. 数字和数字比较, 直接比较大小<br />
2. 数字和字符串比较, 字符串转换为数字后再比较<br />
3. 字符串和字符串比较, 进行字符的ASCII码值比较</p>
</li>
</ul>
<h3 id="_9"><a name="user-content-_9" href="#_9" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>逻辑运算（返回布尔值）</h3>
<ul>
<li>&amp;&amp;: 逻辑与<blockquote>
<p>&amp;&amp;比||优先级高</p>
</blockquote>
</li>
<li>||：逻辑或</li>
<li>!: 逻辑非<br />
<pre><code>!true //=&gt; false
!false //=&gt; true
</code></pre></li>
</ul>
<h3 id="_10"><a name="user-content-_10" href="#_10" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>一元运算</h3>
<ul>
<li>++: 自增1（在原来的数值基础上加1）</li>
<li>&ndash;：自减1（在原来的数值基础上加1）</li>
<li>前置：<br />
    <pre><code>var num = 10;
++num;--num;
</code></pre><br />
    返回值：返回值是减1（加1）之后的值</li>
<li>后置：<br />
    <pre><code>var num = 10;
num++;num--
</code></pre><br />
    返回值：返回值是没减1（加1）之前的值</li>
</ul>
<h3 id="_11"><a name="user-content-_11" href="#_11" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>三目运算</h3>
<p>格式：条件?条件成立时执行:条件不成立时执行<br />
<pre><code>var a=10;
var b=8;
var c = a&gt;b ? 20 : 30;
</code></pre></p>
<h3 id="_12"><a name="user-content-_12" href="#_12" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>八进制和十六进制的介绍</h3>
<ul>
<li>二进制<br />
&lsquo;10101101&rsquo;</li>
<li>八进制<br />
&lsquo;0123&rsquo;</li>
<li>十进制</li>
<li>
<p>十六进制<br />
&lsquo;ef9302&rsquo;</p>
</li>
<li>
<p>十进制转其他<br />
<pre><code>var number = 20;
number.toString(2); //转成2进制
number.toString(8);//转成8进制
</code></pre></p>
</li>
<li>
<p>其他转十进制<br />
<pre><code>var x='110';  
parseInt(x,2);  
parseInt(x,8);  
parseInt(x,16);
</code></pre></p>
</li>
<li>
<p>其他转其他<br />
先用parseInt转成十进制再用toString转到目标进制</p>
</li>
</ul>
<hr />
<p>[案例]</p>
<ul>
<li>今天课堂所有的代码，照敲一遍, 理解并熟练掌握今日知识点.</li>
<li>入职薪水10K，每年涨幅入职薪水的5%，50年后工资多少？</li>
<li>为抵抗洪水，战士连续作战89小时，编程计算共多少天零多少小时？</li>
<li>小明要到美国旅游，可是那里的温度是以华氏度为单位记录的。它需要一个程序将华氏温度（80度）转换为摄氏度，并以华氏度和摄氏度为单位分别显示该温度。<blockquote>
<p>提示：摄氏度与华氏度的转换公式为：摄氏度 = 5/9.0*(华氏度-32)</p>
</blockquote>
</li>
<li>给定一个三位数，分别把这个数字的百位、十位、个位算出来并显示。</li>
</ul>
<hr />
<h2 id="_13"><a name="user-content-_13" href="#_13" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>参考</h2>
<h3 id="_14"><a name="user-content-_14" href="#_14" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>关键字</h3>
<table>
<thead>
<tr>
<th></th>
<th></th>
<th></th>
<th></th>
</tr>
</thead>
<tbody>
<tr>
<td>break</td>
<td>do</td>
<td>instanceof</td>
<td>typeof</td>
</tr>
<tr>
<td>case</td>
<td>else</td>
<td>new</td>
<td>var</td>
</tr>
<tr>
<td>catch</td>
<td>finally</td>
<td>return</td>
<td>void</td>
</tr>
<tr>
<td>continue</td>
<td>for</td>
<td>switch</td>
<td>while</td>
</tr>
<tr>
<td>debugger</td>
<td>function</td>
<td>this</td>
<td>with</td>
</tr>
<tr>
<td>default</td>
<td>if</td>
<td>throw</td>
<td>delete</td>
</tr>
<tr>
<td>in</td>
<td>try</td>
<td></td>
<td></td>
</tr>
</tbody>
</table>
<h3 id="_15"><a name="user-content-_15" href="#_15" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>保留字</h3>
<table>
<thead>
<tr>
<th></th>
<th></th>
<th></th>
<th></th>
</tr>
</thead>
<tbody>
<tr>
<td>class</td>
<td>enum</td>
<td>extends</td>
<td>super</td>
</tr>
<tr>
<td>const</td>
<td>export</td>
<td>import</td>
<td></td>
</tr>
</tbody>
</table>
<h3 id="_16"><a name="user-content-_16" href="#_16" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>操作符优先级</h3>
<table>
<thead>
<tr>
<th>运算符</th>
<th>描述</th>
</tr>
</thead>
<tbody>
<tr>
<td>., [], ()</td>
<td>对象成员存取、数组下标、函数调用、分组等</td>
</tr>
<tr>
<td>++, &ndash;, ~, !, delete, new, typeof, void</td>
<td>一元运算符</td>
</tr>
<tr>
<td>*, /, %</td>
<td>乘法、除法、取模</td>
</tr>
<tr>
<td>+, -</td>
<td>加法、减法、字符串连接</td>
</tr>
<tr>
<td>&lt;, &lt;=, &gt;, &gt;=, instanceof</td>
<td>关系比较、检测类实例</td>
</tr>
<tr>
<td>==, !=, ===, !==</td>
<td>等于、恒等(全等)</td>
</tr>
<tr>
<td>&amp;&amp;</td>
<td>逻辑与</td>
</tr>
<tr>
<td><code>||</code></td>
<td>逻辑或</td>
</tr>
<tr>
<td>?:</td>
<td>三元运算条件</td>
</tr>
<tr>
<td>=, +=, -=, *=, /=, %=</td>
<td>赋值、运算赋值</td>
</tr>
<tr>
<td>,</td>
<td>多重赋值、数组元素</td>
</tr>
</tbody>
</table>
<h3 id="_17"><a name="user-content-_17" href="#_17" class="headeranchor-link" aria-hidden="true"><span class="headeranchor"></span></a>术语</h3>
<ul>
<li>表达式的概念: <ul>
<li>由运算符和操作数（变量或常量）组成的式子</li>
<li>算术运算符组成的式子叫算术表达式</li>
<li>关系运算符组成的式子叫关系表达式或者条件表达式</li>
<li>逻辑运算符组成的式子叫做逻辑表达式<blockquote>
<p>如：2+3；a+5；c&gt;3;  a&amp;&amp;b等</p>
</blockquote>
</li>
</ul>
</li>
<li>返回值：运算后得到的值</li>
<li>程序的三大流程控制<blockquote>
<p>我们的计算机在执行一个程序的时候，最基本的方式是一条语句接一条语句的执行。但不可能所有的问题都能用顺序执行方式就能解决，总会有一些跳转。采用结构化的程序设计，可以大大提高开发程序的速度、提高程序的可读性、程序运行的速度和效率</p>
</blockquote>
<ul>
<li>顺序：从上朝下执行的代码就是顺序</li>
<li>分支(选择)：根据不同的情况，执行对应代码</li>
<li>循环：重复做一件事情</li>
</ul>
</li>
</ul></article></body></html>